Tissue stop for surgical instrument

ABSTRACT

A surgical instrument including a handle assembly, an elongated portion, an end effector, and a stop member is disclosed. The end effector is disposed adjacent a distal portion of the elongated portion and includes a first jaw member and a second jaw member. At least one jaw member is movable with respect to the other jaw member between spaced and approximated positions. The first jaw member includes an upper tissue-contacting surface and a lower shelf portion. The shelf portion includes a groove disposed therein. The stop member is disposed adjacent a distal portion of the first jaw member and is pivotable with respect to the first jaw member between a first position, a significant portion of the stop member being positioned external to the first jaw member, and a second position where a lower portion of the stop member being positioned at least partially within the groove.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Continuation of U.S. patent applicationSer. No. 14/805,593, filed Jul. 22, 2015, which is a Continuation ofU.S. patent application Ser. No. 13/493,346, filed Jun. 11, 2012, nowU.S. Pat. No. 9,107,664, which is a Continuation of U.S. patentapplication Ser. No. 12/952,371, filed Nov. 23, 2010, now U.S. Pat. No.8,215,532, which is a Continuation-In-Part of U.S. patent applicationSer. No. 12/759,897, filed Apr. 14, 2010, now U.S. Pat. No. 8,360,298,which is a Continuation-In-Part of U.S. patent application Ser. No.12/553,174, filed Sep. 3, 2009, now U.S. Pat. No. 7,988,028, which is aContinuation-In-Part and claims benefit of, and claims priority to U.S.patent application Ser. No. 12/235,751, filed Sep. 23, 2008, now U.S.Pat. No. 7,896,214. The entire contents of this application areincorporated herein by reference.

BACKGROUND

The present disclosure relates generally to surgical instruments and,more specifically, to surgical instruments for surgically joiningtissue.

Background of Related Art

Surgical stapling instruments used for applying parallel rows of staplesthrough compressed living tissue are well known in the art. Thesesurgical instruments are commonly employed for closing tissue or organsprior to transaction or resection, for occluding organs in thoracic andabdominal procedures, and for fastening tissue in anastomoses.

Typically, such surgical stapling instruments include an anvil assembly,a cartridge assembly for supporting an array of surgical staples, anapproximation mechanism for approximating the anvil and cartridge andanvil assemblies, and a firing mechanism for ejecting the surgicalstaples from the cartridge assembly.

In use, a surgeon generally initially approximates the anvil andcartridge members. Next, the surgeon can fire the instrument to placestaples in tissue. Additionally, the surgeon may use the same instrumentor a separate instrument to cut the tissue adjacent or between therow(s) of staples. Alternatively, the surgical stapling instrument cansequentially eject the staples while the anvil and cartridge areapproximated.

SUMMARY

The present disclosure relates to a surgical instrument including ahandle assembly, an elongated portion, an end effector, and a stopmember. The elongated portion extends distally from the handle assembly.The end effector is disposed adjacent a distal portion of the elongatedportion and includes a first jaw member and a second jaw member. Atleast one jaw member is movable with respect to the other jaw memberbetween spaced and approximated positions. The first jaw member includesan upper tissue-contacting surface and a lower shelf portion. The shelfportion includes a groove disposed therein. The stop member is disposedadjacent a distal portion of the first jaw member and is pivotable withrespect to the first jaw member between a first position, a significantportion of the stop member being positioned external to the first jawmember, and a second position where a lower portion of the stop memberbeing positioned at least partially within the groove.

In certain embodiments, the cartridge is curved with respect to thelongitudinal axis. A biasing member may be provided and disposed inmechanical cooperation with the stop member, wherein the biasing memberbiases stop member towards its first position. The stop member can bepivotally coupled to the first jaw member.

In certain embodiments, the first jaw member includes a knife channel.The stop member can have a first leg and a second leg, the first leg andthe second leg being positioned on opposite sides of the knife channel.

In certain desirable embodiments, a sled is translatable along the shelfof the first jaw member. The sled can include a plurality of cam wedges,and wherein each cam wedge is connected to an adjacent cam wedge by atransversely-disposed connecting member. The connecting member can bedisposed adjacent a proximal portion of the sled. A distal portion eachof the cam wedges can cantileveredly extend from the connecting member.The wedges may extend from the connecting member and define a space inwhich the stop member is disposed when the sled is disposed at thedistal end of the first jaw member.

In certain embodiments, the instrument includes a beam assembly forpushing the sled toward the distal end of the first jaw member, the beamassembly having a notch, the connecting member of the sled being inengagement with the beam assembly at the notch.

The present disclosure also relates to a tool assembly for use with asurgical instrument. The tool assembly comprises an end effector and astop member. The end effector includes a first jaw member and a secondjaw member, at least one jaw member is movable with respect to the otherjaw member between spaced and approximated positions. The first jawmember includes an upper tissue-contacting surface and a lower shelfportion. The shelf portion includes a groove disposed therein. The stopmember is disposed adjacent a distal portion of the first jaw member andis pivotable with respect to the first jaw member between a firstposition wherein at least a portion of the stop member is positionedexternal to the first jaw member, and a second position wherein at leasta portion of the stop member is positioned within the groove. Therelative movement of the jaw members toward the approximated positioncauses at least a portion of the stop member to move toward the firstjaw member.

In certain embodiments, the cartridge of the tool assembly is curvedwith respect to the longitudinal axis. A biasing member may be providedand disposed in mechanical cooperation with the stop member, wherein thebiasing member biases stop member towards its first position. The stopmember can be pivotally coupled to the first jaw member.

In certain embodiments, the first jaw member of the tool assemblyincludes a knife channel. The stop member can have a first leg and asecond leg, the first leg and the second leg being positioned onopposite sides of the knife channel.

In certain embodiments, the tool assembly had a sled which istranslatable along the shelf of the first jaw member. The sled caninclude a plurality of cam wedges, and wherein each cam wedge isconnected to an adjacent cam wedge by a transversely-disposed connectingmember. The connecting member can be disposed adjacent a proximalportion of the sled. A distal portion each of the cam wedges cancantileveredly extend from the connecting member. The wedges may extendfrom the connecting member and define a space in which the stop memberis disposed when the sled is disposed at the distal end of the first jawmember.

In certain embodiments, the tool assembly includes a beam assembly forpushing the sled toward the distal end of the first jaw member, the beamassembly having a notch, the connecting member of the sled being inengagement with the beam assembly at the notch.

In a further aspect of the disclosure, a surgical instrument includes ahandle assembly, an elongated portion, an end effector, and a stopmember. The elongated portion extends distally from the handle assembly.The end effector is disposed adjacent a distal portion of the elongatedportion and includes a first jaw member and a second jaw member. Atleast one jaw member is movable with respect to the other jaw memberbetween spaced and approximated positions. The first jaw member includesan upper tissue-contacting surface and a lower shelf portion. The stopmember is disposed adjacent a distal portion of the first jaw member andis pivotable with respect to the first jaw member between a firstposition, a significant portion of the stop member being positionedexternal to the first jaw member. The instrument also comprises a sledtranslatable along the shelf portion of the first jaw member, the sledincluding a connecting member disposed at a proximal portion of thesled, and a beam assembly for pushing the sled distally the beamassembly having a notch and the connecting member being disposed in thenotch, the sled defining a space for receiving the stop member when thesled is disposed at the distal portion of the first jaw member.

The shelf portion of the first jaw member may include a groove disposedtherein for receiving a portion of the stop member. The first jaw memberdesirably includes a knife channel. The stop member may have two legspositioned on opposite sides of the knife channel.

In another aspect of the present disclosure, a loading unit has a firstjaw member including an upper tissue-contacting surface and a lowershelf portion. The shelf portion includes a groove disposed therein. Astop member is disposed adjacent a distal portion of the first jawmember and is pivotable with respect to the first jaw member between afirst position wherein at least a portion of the stop member ispositioned external to the first jaw member, and a second positionwherein at least a portion of the stop member is positioned within thegroove. The stop member is pivotably mounted so that at least a portionof the stop member can move toward the first jaw member. In certainembodiments, the stop member has two legs for receiving a knife memberincluded in the loading unit. The loading unit may also include a sledhaving a connecting member at a proximal portion thereof. In certainembodiments, the sled defines a space for receiving the stop member whenthe sled is disposed at the distal portion of the first jaw member. Theloading unit may include a beam assembly, the beam assembly beingconnected to the sled at the connecting member.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the presently disclosed surgical instrument aredisclosed herein with reference to the drawings, wherein:

FIG. 1 is a perspective view of an embodiment of a surgical instrumentaccording to the present disclosure;

FIG. 1A is a perspective view of an embodiment of a loading unitaccording to certain aspects of the present disclosure;

FIGS. 2-4 are perspective views of a portion of the surgical instrumentof FIG. 1, showing a stop member in a first position;

FIGS. 5-7 are side views of an end effector of the surgical instrumentof FIG. 1, shown at different stages of operation;

FIG. 8 is a perspective view of a portion of the surgical instrument ofFIG. 1, showing a stop member adjacent its second position;

FIG. 9 is a perspective view of a curved jaw member according to anotherembodiment of the present disclosure, showing a stop member in a firstposition;

FIG. 10 is a perspective exploded view of the curved jaw member of FIG.9;

FIG. 11 is a perspective view of the curved jaw member of FIG. 9,showing the cross-section of a distal portion taken along section line11-11 of FIG. 9;

FIG. 12 is a perspective view of the curved jaw member of FIG. 9,showing the stop member in a second position;

FIG. 13 is a longitudinal cross-sectional view of a distal portion ofjaw members and a stop member in accordance with another embodiment ofthe present disclosure;

FIG. 14 is a top view of the jaw members of FIG. 13, with the stopmember omitted;

FIG. 15 is a perspective view of a sled for use with the embodiment ofthe jaw members illustrated in FIGS. 14 and 15; and

FIG. 16 is a transverse cross-sectional view of a portion of jaw memberof FIG. 14 and a sled in accordance with another embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument are describedin detail with reference to the drawings, wherein like referencenumerals designate similar or identical elements in each of the severalviews. In the drawings and the description that follows, the term“proximal” refers to the end of the surgical instrument that is closestto the operator, whereas the term “distal” refers to the end of thesurgical instrument that is farthest from the operator. As appreciatedby one skilled in the art, the depicted surgical instrument firesstaples, but it may be adapted to fire any other suitable fastener suchas clips and two-part fasteners. Additionally, the disclosed stop membermay be used with an electrosurgical forceps. Further details ofelectrosurgical forceps are described in commonly-owned patentapplication Ser. No. 10/369,894, filed on Feb. 20, 2003, entitled VESSELSEALER AND DIVIDER AND METHOD OF MANUFACTURING THE SAME, the entirecontents of which are hereby incorporated by reference herein.

With reference to FIG. 1, reference numeral 100 designates an embodimentof the presently disclosed surgical instrument. The present disclosurerelates to an end effector and a stop member of surgical instrument 100.U.S. Patent Applications Publication Nos. 2008/0105730, filed on Nov.28, 2007; 2008/0110960, filed on Jan. 8, 2008; 2008/0142565, filed onJan. 24, 2008; 2008/0041916, filed on Oct. 15, 2007 and U.S. ProvisionalPatent Application Ser. No. 61/050,273, filed on May 5, 2008 describe indetail the structure and operation of other surgical fasteningassemblies. The entire contents of these prior applications areincorporated herein by reference. Any of the surgical fasteningassemblies disclosed in the cited patent applications may include thepresently disclosed stop member.

Surgical instrument 100 is configured to clamp, fasten, and/or cuttissue. In general, surgical instrument 100 includes a handle assembly160, an elongate portion 120 extending distally from handle assembly 160and defining a longitudinal axis “A-A,” and a tool assembly 150 adaptedto clamp and fasten tissue. Elongate portion 120 has a proximal portion122 and a distal portion 124 and operatively couples handle assembly 160with tool assembly 150. Tool assembly 150 includes end effector 154 andstop member 170. End effector 154, which is disposed adjacent distalportion 124 of elongated portion 120, includes a first jaw member 130and a second jaw member 140. At least one of the jaw members 130, 140 isadapted to move relative to the other jaw member (130 or 140) betweenspaced and approximated positions. In the illustrated embodiment, firstjaw member 130 contains a cartridge assembly 132, while second jawmember 140 includes an anvil assembly 142. The tool assembly 150 can bemounted onto the distal end of the elongate portion 120, or the toolassembly 150 can be incorporated into a replaceable loading unit 121. Byway of example, FIG. 1A shows a loading unit 121 having a proximal bodyportion 123 that is connectable to the distal end of the elongateportion 120. This loading unit 121 includes the anvil assembly,cartridge assembly, as well as the knife and other actuation apparatusdiscussed below. In other examples, the tool assembly is incorporatedinto the surgical instrument and the cartridge assembly has areplaceable cartridge received in the first jaw member 130. The toolassembly may have linear jaws or arcuate jaws. Tool assemblies with ananvil assembly, cartridge assembly and actuation apparatus with a knifeare disclosed in U.S. patent application Ser. No. 12/235,751, filed Sep.23, 2008 and U.S. patent application Ser. No. 12/553,174, filed Sep. 3,2009, the disclosures of which are hereby incorporated by referenceherein.

As discussed below, the anvil assembly 142 shown in FIG. 1 moves withrespect to cartridge assembly 132 between spaced and approximatedpositions upon actuation of handle assembly 160, for example. However,the cartridge assembly may move toward and away from the anvil assemblyto clamp tissue. It is also envisioned that other methods ofapproximating the jaw members are also usable, including sliding a clampbar 168.

Handle assembly 160 includes a stationary handle 162 and a movablehandle 164. Movable handle 164 is adapted to move pivotally toward oraway from stationary handle 162. Further, movable handle 164 isoperatively connected to anvil assembly 140 through a mechanism adaptedto convert at least a partial actuation of movable handle 164 into apivoting motion of at least one of cartridge assembly 132 and anvilassembly 142 between spaced and approximated positions. As recognized byone skilled in the art, any conventional actuation mechanism may beemployed to operatively couple movable handle 164 to tool assembly 150.

With reference to FIGS. 2-5, cartridge assembly 132 has atissue-contacting surface 134 and a plurality of fastener retainingslots 136. The anvil assembly 142 includes an anvil plate 143.Tissue-contacting surface 134 generally faces the anvil plate 143 onanvil assembly 142 (see FIG. 1) and, during operation, engages tissuewhen the anvil assembly 142 is approximated with cartridge assembly 132.Fastener retaining slots 136 are arranged in rows along tissuecontacting surface 134. Each fastener retaining slot 136 is adapted tohold a fastener (not shown), such as a staple or other surgicalfastener, until a user actuates handle assembly 160 (see FIG. 1), forexample. When movable handle 164 is pivoted toward stationary handle162, the fasteners are ejected from fastener retaining slots 134, movetoward anvil assembly 142, and are formed in staple forming recesses inthe anvil plate 143. The fasteners can be stainless steel, titanium, orother deformable surgical metal staples, polymeric staples, two-partfasteners or other surgical fasteners.

In addition to fastener retaining slots 134, cartridge assembly 132 hasa knife channel 138 adapted to slidably receive a knife (not shown) orany other suitable cutting tool. Knife channel 138 is disposed betweenrows of fastener retaining slots 136 and extends along tissue-contactingsurface 134. In operation, a knife (not shown) slides through knifechannel 138 when movable handle 164 pivots toward stationary handle 162.Alternatively, other mechanisms can be used to drive the knife throughknife channel 138. In addition to knife channel 138, cartridge assembly132 has a pair of slots 139 formed on tissue-contacting surface 134.Each slot 139 provides access to an inner portion of cartridge assembly132 and is configured to receive portions of stop member 170.

In disclosed embodiments, handle assembly 160 contains an actuationmechanism for deploying the fasteners from fastener retaining slots 136and advancing a knife along knife channel 138. This actuation mechanismincludes a firing rod operatively connected to movable handle 164. Inoperation, pivoting movable handle 164 toward stationary handle 162causes firing rod to advance distally. Firing rod is in turn operativelycoupled to an axial drive assembly at least partially positioned withintool assembly 150. Axial drive assembly is configured to move distallyin response to a distal translation of firing rod. The axial driveassembly includes a beam that has an upper portion for engaging theanvil assembly and a lower portion for engaging the cartridge assembly.As the axial drive assembly translates distally through the anvilassembly and cartridge assembly, the engagement of the upper portion andlower portion causes the second jaw member 140 to pivot toward first jawmember 130. In addition, the axial drive assembly pushes an actuationsled disposed within first jaw member 130 in a distal direction, whilethe actuation sled translates distally through end effector 154. As theactuation sled advances distally through first jaw member 130, thisactuation sled urges the fasteners out of the fastener retaining slots136. In certain embodiments, axial drive assembly includes a blademounted on a distal portion thereof. In operation, this knife movesthrough knife channel 138 of the cartridge assembly 132 when axial driveassembly moves distally through end effector 154. Likewise, the anvilplate 143 of the anvil assembly 142 defines a slot to allow translationof the axial drive assembly. The knife blade faces distally in the toolassembly 150 so that tissue between the jaws of the tool assembly 150 isprogressively cut as the fasteners are formed.

Stop member 170 is disposed adjacent a distal portion 137 of first jawmember 130 (which is shown as cartridge assembly 132, but may also beanvil assembly 142). The stop member 170 is pivotable with respect tothe first jaw member 130 between a first position, as illustrated inFIG. 5, and a second position, as depicted in FIG. 7. In the firstposition, at least a portion of stop member 170 is located external tothe first jaw member 130, whereas, in the second position, at least aportion of stop member 170 is positioned at least partially belowtissue-contacting surface 134 of first jaw member 130. In variousembodiments, a significant portion of stop member 170 is disposedexternal to the first jaw member 130 when stop member 170 is located inthe first position. It is envisioned that the term “significant” meansthat at least half of each leg 177 of stop portion 170 is disposedexternal to the first jaw member 130 when stop member 170 is located inthe first position. Additionally, as used herein, “significant” may meanthat more than one-third of stop member 170 is disposed external to thefirst jaw member 130 when stop member 170 is located in the firstposition.

Stop member 170 includes a base 172 adapted to engage an outer surfaceof distal portion 137 of first jaw member 130 and a stopping portion 174adapted to engage tissue. A pivot pin 176, or any other suitableapparatus, pivotally connects stopping portion 174 to base 172.Consequently, stopping portion 174 is configured to pivot away andtoward tissue-contacting surface 134. In one embodiment, stop member 170includes a biasing member (e.g., a spring) for biasing stopping portion174 away from first jaw member 130.

Stopping portion 174 contains a body 175 and at least one leg 177extending proximally from body 175. In the embodiment depicted in FIG.2, stopping portion 174 has two legs 177 extending proximally from body175. Stopping portion 174 may nonetheless include more or fewer legs177. The two legs 177 shown in FIG. 2 define a space therebetweenadapted to receive a knife. Each leg 177 is dimensioned to be receivedwithin a slot 139 and includes a proximal surface 173. When stop member170 is located in the first position, each proximal surface 173 definesan oblique angle relative to tissue-contacting surface 134, as seen inFIG. 5. Conversely, when stop member 170 is located in the secondposition (see FIG. 7), each proximal surface 173 defines an anglesubstantially perpendicular to tissue-contacting surface 134.Irrespective of the position of stop member 170, legs 177 are shownpositioned on opposite sides of knife channel 138. Slots 139, which aredimensioned to receive legs 177, are accordingly located on oppositesides of knife channel 138 as well.

Referring to FIGS. 6-8, stop member 170 facilitates retention of tissuebetween first and second jaw members 130, 140 during the operation ofsurgical instrument 100. (See FIG. 1). That is, stop member 170 helpsprevent tissue from migrating or translating distally past its intendedplacement between the jaw members. In use, a user initially positionssurgical instrument 100 adjacent a target tissue. Particularly, thetarget tissue is placed between first and second jaw members 130, 140.The angle defined by body 175 relative to tissue-contacting surface 136facilitates introduction of the target tissue “T” into tool assembly 150in the general direction of arrow “A,” as seen in FIG. 6. Once the userhas placed at least a portion of the target tissue between first andsecond jaw members 130, 140, the user pulls movable handle 164 towardstationary handle 162 to approximate anvil assembly 152 toward cartridgeassembly 132. While the user pulls movable handle 164, anvil assembly152 moves closer to cartridge assembly 132 and the target tissue “T” iscaptured between tissue-contacting surface 134 of cartridge assembly132. At the same time, anvil assembly 142 urges stopping portion 174toward cartridge assembly 132. In response to the force exerted by theanvil assembly 142 on stopping portion 174, stopping portion 174 pivotsabout pivot pin 176 toward cartridge assembly 132, e.g., against thebias of biasing member (not shown). While stopping portion 174 movescloser to cartridge assembly 134, at least a portion of legs 177 move toan inner portion of cartridge assembly 132 through slots 139, as seen inFIG. 7. When stop member 170 is in the second position (as shown in FIG.7), a portion of legs 177 is located within cartridge assembly 132;correspondingly, a portion of proximal surfaces 173 is located outsideof cartridge assembly 132. As discussed above, proximal surfaces 173define a substantially orthogonal angle relative to tissue-contactingsurface 134 when stop member 170 is in the second position, therebyhindering the escape of tissue during clamping.

The present disclosure also contemplates stop member 170 beingreleasably attachable to end effector 150 via conventional mechanicalmeans, e.g., bayonet coupling, latch, detent or snap-fit connection.

With reference to FIGS. 9-12, a first jaw member 230 according toanother embodiment is envisioned. First jaw member 230 of thisembodiment has a curved shape (i.e., with respect to longitudinal axis“A-A”). The first jaw member may be part of a loading unit including ananvil assembly, or some other surgical fastening device. It isenvisioned that curved jaw members may facilitate performing certaintypes of surgical procedures. For example, curved jaw members, ascompared to straight jaw members (such as the jaw members illustrated inFIG. 1), may help facilitate access to lower pelvic regions, e.g.,during lower anterior resection (“LAR”) or other colo-rectal surgery.

First jaw member 230 includes an opening 239 (FIG. 10) adapted toreceive both legs 277 of stop portion 270 instead of two slots 139 eachcapable of receiving a leg 177 of stop member 170. Stop member 270 issimilar to stop member 170. However, stop member 270 has a stoppingportion 274 directly connected to a distal portion 237 of first jawmember 230. Distal portion 237 contains a hole 235 (FIG. 10) adapted toreceive a pivot pin 276. Pivot pin 276, or any other suitable apparatus,pivotally couples stop member 270 to first jaw member 230.

The term “distal” typically refers to that part or component of theinstrument that is farther away from the user. As used herein, the terms“distal” and “proximal” will take into account the curvature of curvedparts of the surgical instrument 10 of the present disclosure. Forexample, “distal” will refer to the portion of the curved part that isfarthest from the user, along a trajectory defined by the curved part,such as trajectory C-C shown in FIG. 12. That is, while an intermediateportion of a curved part may be farther from the user during use, theportion of the curved part that is farthest along its longitudinal axisis considered “distal.”

In general, first jaw member 230 includes a curved housing 231 and acurved cartridge assembly 232. Housing 231 has a curved channel 233adapted to receive curved cartridge assembly 232. Curved cartridgeassembly 232 contains a tissue-contacting surface 234 configured toengage tissue, rows of fastener retaining slots 236 extending along itscurved profile, and a knife channel 238 adapted to slidably receive aknife (not shown). Knife channel 238 is disposed between the rows offastener retaining slots 236.

As discussed above, actuating handle assembly 160 not only ejects thefasteners, but also drives a knife along knife channel 238 (e.g., via asingle stroke or multiple strokes of movable handle 164). Knife channel238 leads to an opening 239 formed on distal portion 237 of cartridgeassembly 232. A recess 280 is positioned distally of opening 239 andincludes an inclined wall 282 (see FIG. 11) defining an oblique anglerelative to tissue-contacting surface 234 and is adapted to receive aportion of stop member 270 therein. In addition to inclined wall 282,recess 280 has a cavity 284 adapted to receive a portion of stop member270 (see FIG. 11).

Stop member 270 includes a body 275, a pair of legs extending proximallyfrom body 275, and a pivoting protrusion 286 extending transversely frombody 275. Legs 277 define a space therebetween dimensioned to receive aknife. Each leg 277 has a proximal surface 273 that defines an obliqueangle relative to tissue-contacting surface 234 when stop portion 270 isin the first position, as shown in FIG. 9, and a substantiallyperpendicular angle relative to tissue-contacting surface 234 when stopportion 270 is in the second position, as illustrated in FIG. 12.

Body 275 defines an oblique angle with respect to the tissue-contactingsurface 234. Pivoting protrusion 286 of stop member 270 is adapted to bereceived within cavity 284 and has a hole 288 configured to receivepivot pin 276. Pivot pin 276 extends through hole 235 of cartridgeassembly 270 and hole 280 of pivoting protrusion 286 and allows stopmember 270 to pivot from a first position where at least a portion ofthe stop member 270 is positioned external to first jaw member 230, asseen in FIG. 9, and a second position where at least a portion of stopmember 270 is positioned at least partially below a tissue-contactingsurface 234 of the first jaw member 230, as seen in FIG. 12.

As seen in FIG. 11, body 275 additionally contains a thru-hole 290leading to inclined wall 282 and an abutment wall 292 protruding towardthru-hole 290. Abutment wall 292 is configured to hold a first end 294 aof a biasing member 294, and inclined wall 282 is adapted to support asecond end 294 b of biasing member 294. Biasing member 294 biases stopmember 270 towards its first position. In the embodiment depicted inFIGS. 10 and 11, biasing member 294 is a spring, but biasing member 294can alternatively be any suitable apparatus or means capable of biasingstop member 270 away from first jaw member 230.

The operation of first jaw member 230 is substantially similar to theoperation of first jaw member 130. First jaw member 230 works jointlywith an anvil assembly to cut and/or fasten tissue. As a user actuateshandle assembly 160, the jaw members approximate, which urges stopmember 230 from the first position (see FIG. 9) to a second position(see FIG. 12). In the first position, the orientation of stop member 230facilitates the introduction of tissue between first jaw member 230 andan anvil assembly. Further, stop member 230 inhibits tissue fromdistally escaping the tool assembly when stop member 230 is oriented inits second position. When the anvil assembly moves away from first jawmember 230, stop member 230, under the influence of biasing member 294,returns to its first position.

FIGS. 13-14 illustrate another embodiment of a first jaw member 330, anda second jaw member 340 for a surgical stapling instrument. Anotherembodiment of a tissue stop 370 is illustrated in FIG. 13. FIG. 13illustrates tissue stop 370 in its first, initial position (phantomlines) and in its second position (solid lines). Similar to theembodiments disclosed hereinabove, tissue stop 370 is biased towards itsinitial position, and in approximation of the jaw members, contact withthe opposing jaw member causes tissue stop 370 to move towards itssecond position. By way of example, the first jaw member 330 is a staplecartridge assembly, and the second jaw member 340 is an anvil assembly.Other surgical instrument jaws, such as electrosurgical, arecontemplated.

With particular reference to FIG. 13, first jaw member 330 (e.g.,cartridge assembly) includes an upper tissue-contacting surface 332 anda lower shelf portion 334. Lower shelf portion 334 includes a groove 336extending at least partially therethrough. As shown in FIG. 13, groove336 is configured to accept a portion of tissue stop 370 therein. Inparticular, groove 336 is configured to accept a lip 372 of tissue stoptherein. Groove 336 enables tissue stop 370 to include a stoppingportion 374 having a maximum height “H1.” More particularly, tissue stop370 is configured to fit within first jaw member 330 (i.e., not protrudeabove upper tissue-contacting surface 332, and not protrude below lowershelf portion 334) when tissue stop 370 is in its second position (i.e.,corresponding to first and second jaw members 330, 340, respectively,being approximated with respect to one another), and to extend betweenthe tissue-contacting surface 332 and the anvil plate when the tissuestop 370 is in its first position (such as when the first jaw member andsecond jaw member are spaced from one another and ready to receivetissue). Thus, without the inclusion of groove 336, the maximum heightof stopping portion 374 would be decreased by the height “H2” of lowershelf portion 334. As can be appreciated, the greater the height “H1” ofstopping portion 374, the increased ability surgical instrument has tocontain thicker tissue between the jaw members. That is, the relativelylarge height “H1” of stopping portion 374 helps prevent a greater amountof tissue (e.g., a greater thickness of tissue) from distally escapingthe jaw members.

An actuation sled 400 is illustrated in FIGS. 13-15. Actuation sled 400is longitudinally translatable (including along a curved path) withrespect to first jaw member 330 (e.g., cartridge assembly). As discussedabove, an axial drive assembly pushes actuation sled 400 in a distaldirection, and as actuation sled 400 advances distally through and alonglower shelf portion 334 of first jaw member 330, actuation sled 400urges fasteners out of the fastener retaining slots. For example, a beamincluding a knife may be used to advance the actuation sled to fire thefasteners.

In the illustrated embodiments, actuation sled 400 includes four camwedges 402 a, 402 b, 402 c, and 402 d and a transversely-extendingconnecting member 404 which operably connects each cam wedge with itsadjacent cam wedge(s). As illustrated, connecting member 404 isproximally disposed with respect to each cam wedge 402. The proximallocation of connecting member 404 with respect to cam wedges 402 createsdistal portions of each of cam wedge 402 that are elongated and thatcantileveredly extend from connecting member 404. It is also envisionedthat portions (e.g., distal portions) of wedge 402 a are connected toadjacent wedge 402 b, and that portions of wedge 402 c are connected toadjacent wedge 402 d via connecting member 404 and/or a separate member,to enhance stability of actuation sled, for instance. The presentdisclosure also includes an actuation sled 400 including more or fewerthan the illustrated four cam wedges.

Actuation sled 400 is configured to accommodate tissue stop 370, and inparticular, lip 372 of tissue stop 370. In particular, the proximalorientation of connecting member 404 enables distal portions of camwedges 402 to contact fasteners or pusher members (not explicitlyillustrated in FIGS. 13-15) that are distally disposed within first jawmember 330 without interfering with lip 372 of tissue stop 370. Morespecifically, when actuation sled 400 is in its distal-most position (asillustrated by the phantom lines in FIG. 14), connecting member 404 ispositioned proximally of lip 372 of stop member 370 (location of lip 372is indicated by a widened portion 339 of a knife channel 338 in FIG.14), thus enabling distal portion of cam wedges 402 to cause ejection ofthe most distally-disposed fasteners (not shown). While the distal-mostportion of cam wedges 402 is illustrated as being substantially alignedwith the distal edge of knife channel 338 when actuation sled 400 is ina distal position, it is envisioned that the distal-most portion of camwedges 402 extends proximally of and/or distally beyond the distal edgeof knife channel 328.

Referring back to FIG. 13, an I-beam assembly 500 is illustrated inconnection with first jaw member 330 and second jaw member 340.According to the embodiment illustrated in FIG. 13, I-beam assembly 500generally includes an upper member 502 configured to slidably engage aslot in second jaw member 340, a lower member 504 configured to slidebeneath lower shelf portion 334 of first jaw member 330, and a knife 506configured to cut tissue between the jaw members 330, 340. Additionally,I-beam assembly 500 also includes a notch 508 along a lower surfacethereof which is configured to mechanically engage connecting member 404of actuation sled 400. As such, distal approximation of the I-beamassembly 500 results in approximation of the jaw members 330, 340,results in cutting of tissue between the jaw members 330, 340, and alsoresults in distal advancement of actuation sled 400, which causesfasteners to be ejected from first jaw member 330. In certainembodiments, the knife 506 is disposed between legs 277 of the tissuestop, the legs defining a recess for receiving the knife 506. A plastic,compressible and/or elastic material may be disposed in the recessdefined by the legs 277 for pressing tissue against the knife 506, atthe end of travel for the I beam assembly 500. Additionally, retractionof I-beam assembly 500 in a proximal direction causes a correspondingproximal retraction of actuation sled 400. It is also envisioned thatwhen I-beam assembly 500 is proximally retracted to a predeterminedlocation, at least one jaw member moves towards the open position withrespect to the other jaw member.

With reference to FIG. 16, a transverse cross-sectional view of aportion of jaw member 330 and sled 400 is shown. In this embodiment,connecting member 404 is shown with an alignment nub 406 downwardlydepending therefrom. Alignment nub is configured to follow the curvatureof the knife channel 338 as the actuation sled 400 translates withrespect to the jaw member 330. The engagement between the alignment nub406 and the knife channel 338 may help maintain the relative lateralposition (e.g., centered) of the actuation sled with respect to the jawmember 330 during translation of the actuation sled 400.

It will be understood that various modifications may be made to theembodiments of the presently disclosed surgical instruments. Therefore,the above description should not be construed as limiting, but merely asexemplifications of embodiments. Those skilled in the art will envisionother modifications within the scope and spirit of the presentdisclosure.

What is claimed is:
 1. A surgical instrument for surgically joiningtissue, the surgical instrument comprising: an end effector having afirst jaw member and a second jaw member, at least one of the first jawmember or the second jaw member being movable with respect to the otherjaw member, the first jaw member having a knife channel with a widenedportion adjacent a distal end thereof; a sled disposed in mechanicalcooperation with the first jaw member and including two wedge portionsand a connecting member therebetween, the sled having a distal mostposition with respect to the first jaw member in which the connectingmember is disposed proximal of the widened portion of the knife channel;a beam assembly for pushing the sled towards a distal end of the firstjaw member, the beam assembly including a knife; and a stop memberdisposed adjacent a distal portion of the first jaw member andconfigured to impede tissue from distally escaping the first jaw memberand the second jaw member.
 2. The surgical instrument according to claim1, wherein the beam assembly includes a notch, and wherein theconnecting member of the sled engages the beam assembly at the notch. 3.The surgical instrument according to claim 1, wherein the stop memberincludes a lip aligned with the widened portion of the knife channel. 4.The surgical instrument of claim 1, wherein at least one of the firstjaw member or the second jaw members is curved along its length.
 5. Thesurgical instrument according to claim 1, wherein the stop member ispivotally supported on the first jaw member and is pivotable between afirst position where a portion of the stop member is external to thewidened portion of the knife channel and a second position where aportion of the stop member is positioned at least partially within thewidened portion of the knife channel.
 6. The surgical instrument ofclaim 5, further comprising a biasing member disposed in mechanicalcooperation with the stop member, wherein the biasing member ispositioned to bias the stop member towards the first position.
 7. Thesurgical instrument of claim 1, wherein the stop member furthercomprises a first leg and a second leg, the first leg and the second legbeing positioned on opposite sides of the knife channel.
 8. The surgicalinstrument of claim 1, wherein each of the two wedge portions of thesled includes two wedges.
 9. The surgical instrument of claim 1, whereinthe stop member is pivotable with respect to the first jaw member. 10.The surgical instrument of claim 1, wherein the stop member is pivotablewith respect to the first jaw member about a pin engaged with a distalportion of the stop member.